Why Some Of The Best Universities Are Giving Away Their Courses

Seattle Tech entrepreneur Greg Linden describes himself as "mostly retired" these days, but at age 39 he still has an insatiable appetite for knowledge. So he decided to go to college — without leaving home.

Through Stanford University, he took a class on robotic-car programming from professor Sebastian Thrun, who led the team that designed Google's self-driving car.

He also scarfed down a class on computer-program design from Google Research director Peter Norvig, who used to oversee computational sciences at NASA. And he gobbled up a class on machine learning from another Stanford professor who directs the university's Artificial Intelligence Lab.

All the classes were online, open to anyone. Linden didn't have to fill out an application or send in his transcripts.